what is None,True,False in python?
Are they keywords, constants, or functions? If they are constants, what are their types? It seems python has no type of boolean.
The Python Documentation has it all, one just has to know where to look:
A small number of constants live in the built-in namespace. They are:
The false value of the bool type. Assignments to False are illegal and raise a SyntaxError.
The true value of the bool type. Assignments to True are illegal and raise a SyntaxError.
The sole value of the type NoneType. None is frequently used to represent the absence of a value, as when default arguments are not passed to a function. Assignments to None are illegal and raise a SyntaxError.
This type has a single value. There is a single object with this value. This object is accessed through the built-in name None. It is used to signify the absence of a value in many situations, e.g., it is returned from functions that don’t explicitly return anything. Its truth value is false.
These represent the truth values False and True. The two objects representing the values False and True are the only Boolean objects. The Boolean type is a subtype of the integer type, and Boolean values behave like the values 0 and 1, respectively, in almost all contexts, the exception being that when converted to a string, the strings "False" or "True" are returned, respectively.